Semiconductor device and method for manufacturing the same

ABSTRACT

A semiconductor device includes a lower conductive member, a upper conductive member and a conductive wire. The one end of the conductive wire is electrically connected to a semiconductor chip. The lower conductive member is formed on a lead frame. The conductive wire is sandwiched between the lower conductive member and the upper conductive member located thereon and is electrically connected to the lead frame. A connecting portion of the conductive wire connected to the lead frame is sandwiched between the lower and upper conductive members so that the neck portion of the conductive wire can be protected from above.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a semiconductor device having asemiconductor chip and a wiring member to be electrically connected tothe semiconductor chip and a method of manufacturing the semiconductordevice.

[0003] 2. Description of the Related Art

[0004] In a semiconductor device, a semiconductor chip and a lead frameincorporating it are electrically connected by a bonding wire. In a wirebonding step, a ball is formed on the tip of a boning wire, the ball isfixed to the pad on a semiconductor chip. Next, the bonding wire isextended onto the lead frame and connected a lead frame. Thereafter, thebonding wire is cut.

[0005] Such a wire bonding technique is disclosed in e.g.JP-A-55-118643. The technique disclosed therein relates to a wirebonding technique of bonding an Au wire to an Al face. As disclosed inthis reference, when the Au wire is fixed to the Al face, intermetalliccompound will be generated at the interface therebetween and theboundary is made fragile so that the bonding strength becomesinsufficient. In order to overcome such an inconvenience, the inventiondisclosed in the reference has been accomplished.

[0006] However, as the case may be, the semiconductor devicemanufactured by the above technique cannot also provide sufficientbonding strength under its utilizing environment.

[0007] For example, the strength of wire bonding may be reducedaccording to the chemical state of the surface of the pad of asemiconductor chip, terminal of a package and lead frame. In such acase, the bonding wire is broken when a smaller strength than thestrength of a wire strand itself is applied. The inventors of theinvention have found that where the wire bonding strength was reduced,the sectional area of the neck portion (just near a ball portion formedat the top end) of the bonding wire had been reduced. If expansion andshrinkage of mold resin of a resin-sealed semiconductor chip, which isthus wire-bonded in such a condition, great strength is applied to abonding wire of the semiconductor chip. Therefore, the semiconductordevice is falied at the portion having a smaller area of the bondingwire.

SUMMARY OF THE INVENTION

[0008] An object of the invention is to provide a semiconductor devicewhich can prevent reduction in the tension leading to breakage of abonding wire and a method for manufacturing such a semiconductor device.

[0009] A semiconductor device according to the invention includes alower conductive member, a upper conductive member and a conductivewire. The lower conductive member is formed on a wiring member to beelectrically connected to the semiconductor chip. The one end of theconductive wire is electrically connected to a semiconductor chip. Theother end of the conductive wire is sandwiched between the lowerconductive member and the upper conductive member located thereon and iselectrically connected to the wiring member. Thus, the semiconductorchip is electrically connected to the wiring member through theconductive wire.

[0010] The connecting portion of the conductive wire to be connected tothe wiring member is sandwiched between the lower and upper conductivemembers so that the neck portion of the conductive wire can be protectedfrom above by the upper conductive member. Therefore, such a structurehaving both lower and upper conductive members has an increased bondingarea of the conductive wire between both conductive members as comparedwith the structure provided with only the lower conductive member andhence provides an increased bonding strength. Further, the lowerconductive member is formed on the lower side of the conductive wire.Therefore, in bonding, the lower conductive member is deformed so thatdeformation of the conductive wire itself is suppressed and reduction inthe sectional area of the neck portion of the conductive wire is alsosuppressed.

[0011] A semiconductor device according to the invention includes alower conductive member, a second connecting member and a conductivewire. The lower conductive member is formed on a wiring member to beelectrically connected to a semiconductor chip. The second connectingmember having a upper conductive member formed on said lower conductivemember and a connecting portion connected to said wiring member at adifferent position from said lower conductive member. The one end of theconductive wire is electrically connected to said semiconductor chip.The other end of the conductive wire is sandwiched between said lowerand upper conductive members and electrically connected to said lowerconductive member.

[0012] The neck portion is protected by the upper conductive member. Inaddition, the lower conductive member to which the other end of theconductive wire is bonded is bonded to the wiring member. The other endof the conductive wire is also bonded to the upper conductive member ofthe second connecting member. The second connecting member is bonded tothe wiring member at a different position from the lower conductivemember. Further, since the conductive wire is connected to the wiringmember at plural connecting positions, the tension applied to theconductive wire is dispersed at the plural connecting positions.Therefore, since the tension applied to each of the plural connectingpositions is reduced on average, even if there is a distribution of thebonding strength, the margin for the limit of the strength leading toflaking of the bonding can be assured.

[0013] The semiconductor device according to the invention includes afirst connecting member, a second connecting member and a conductivewire. The first connecting member has a lower conductive member formedon a wiring member to be electrically connected to a semiconductor chipand a connecting portion connected to the wiring member at a differentposition from said lower conductive member. The second connecting memberhas an upper conductive member formed on said lower conductive memberand a connecting portion connected to said wiring member at a differentposition from said lower conductive member. The one end of theconductive wire is electrically connected to said semiconductor chip.The other end thereof is sandwiched between said lower and upperconductive member and electrically connected to said lower conductivemember.

[0014] The neck portion is protected by the upper conductive member. Inaddition, the other end of the conductive wire is bonded to the wiringmember through the lower conductive member and also bonded to the upperconductive member of the second connecting member. The first and thesecond connecting member are bonded to the wiring member at differentpositions from the lower conductive member, respectively. Therefore, theconductive wire is connected to the wiring member through the lowerconductive member and the first and the second connecting member. Thus,the bonding area between the conductive wire and the wiring member isincreased so that bonding strength therebetween is increased. Further,since the conductive wire is connected to the wiring member at pluralconnecting positions, the tension applied to the conductive wire isdispersed at the plural connecting positions. Therefore, since thetension applied to each of the plural connecting positions is reduced onaverage, even if there is a distribution of the bonding strength, themargin for the limit of the strength leading to flaking of the bondingcan be assured.

[0015] Preferably, the lower and the upper conductive member and theconductive wire are made of the same material. Because of ametallographic nature, the bonding strength will be made greater betweenthe same kinds of metal than between the different kinds of metal. Awavelength of the light, which the light emitting element and the lightreceiving element has sensivity, is permeable to the mold resin.

[0016] The semiconductor device according to the invention preferablyincludes mold resin for sealing the semiconductor chip and wiringmember. The semiconductor chip can include at least one of a lightemitting element and a light receiving element. The light relative tothe light emitting element and light receiving element is preferablypermeable to the mold resin.

[0017] Where the semiconductor device is sealed by mold resin, itsstrength for the stress applied when the mold resin is expanded orshrunken can be increased. Particularly, such a semiconductor device issuitable when it is molded by transparent resin because the transparentresin and the wiring member such as a lead frame have different thermalexpansion coefficients.

[0018] The present invention relates to a method of manufacturing asemiconductor device in which a semiconductor chip and a wiring memberare electrically connected to each other. Therefore, the inventioncomprising the steps of (1) a first step of forming a lower conductivemember on said wiring member; (2)a second step of connecting the one endof a conductive wire to said semiconductor chip; (3) a third step ofconnecting said conductive wire to said lower conductive member; and (4)a fourth step of forming an upper conductive member on said lowerconductive member through said conductive wire.

[0019] Since the lower conductive member is provided before theconductive wire is connected to the wiring member, the conductiveportion can be provided which can absorb the stress applied in bondingto the portion to which the conductive wire is connected. Therefore, thedeformation of the conductive wire can be decreased. Further, since theupper conductive member is provided on the lower conductive memberthrough the conductive wire after the conductive wire has been connectedto the lower conductive member, the neck portion of the conductive wireformed when the conductive wire is connected to the lower conductivemember can be protected.

[0020] The method of manufacturing a semiconductor device according tothe invention can further comprise, after said fourth step, (5) the stepof fixing a conductive portion extending from said upper conductivemember to said wiring member at a different position from said lowerconductive member.

[0021] The upper conductive member protects the neck portion and isbonded to the conductive wire. Therefore, if the conductive portionextending from the upper conductive member is bonded to the wiringmember, the entire bonding strength is increased.

[0022] The method of manufacturing a semiconductor device can furthercomprise, prior to said second step, (6) the step of bonding aconductive portion extending from said lower conductive member to saidwiring member at a different position from said lower conductive member.

[0023] The lower conductive member is bonded to the conductive wire.Therefore, if the conductive portion extending from the lower conductivemember is bonded to the wiring member, the entire bonding strength isincreased.

[0024] The method of manufacturing a semiconductor device according tothe invention can, further comprises (7) a step of preparing thesemiconductor chip having one of a light receiving element and a lightemitting element and the wiring member prior to said first step; and (8)a step of sealing said wiring member and said semiconductor chipconnected to said wiring member through said conductive wire using moldresin.

[0025] After the neck portion is protected by the upper conductivemember, the wiring member and semiconductor chip are sealed by moldresin. When stress is applied to the conductive wire owing to theexpansion and shrinkage of the mold resin for sealing, the breakage ofthe conductive wire at the neck portion is difficult to occur. The lightrelative to the light receiving element and the light emitting elementis permeable to the mold resin.

[0026] In the semiconductor device and the method of manufacturing itaccording to the invention, the wiring member may be a lead frame onwhich the semiconductor device is mounted, or another semiconductor chipdifferent from the semiconductor chip. Thus, the present invention canbe applied to both cases where the wiring member is the semiconductorchip and lead frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the accompanying drawings:

[0028]FIG. 1 is a perspective view showing the manner of connecting asemiconductor chip to a lead frame through a conductive wire;

[0029]FIG. 2A is a side view showing the step after a lower conductivemember has been formed on the lead frame, and

[0030]FIG. 2B is a plan view thereof;

[0031]FIG. 3A is a side view showing the step after the semiconductorchip has been connected to an inner lead through the conductive wire,and

[0032]FIG. 3B is a plan view thereof;

[0033]FIG. 4A is a side view showing the step after an upper conductivemember has been formed, and

[0034]FIG. 4B is a plan view thereof;

[0035]FIG. 5A and FIG. 5B are enlarged views of the manner of bondingthe conductive wire onto the lower conductive member;

[0036]FIG. 6A is a side view showing the step after the lower conductivemember has been formed on a semiconductor chip, and

[0037]FIG. 6B is a plan view thereof;

[0038]FIG. 7A is a side view showing the step after a semiconductor chipand another semiconductor chip have been connected to each other by aconductive wire, and

[0039]FIG. 7B is a plan view thereof;

[0040]FIG. 8A is a side view showing the step after an upper conductivemember has been formed, and

[0041]FIG. 8B is a plan view thereof;

[0042]FIG. 9A is a side view showing the step after a lower conductivemember has been formed on a lead frame, and

[0043]FIG. 9B is a plan view;

[0044]FIG. 10A is a side view showing the step after the semiconductorchip has been connected to an inner lead through the conductive wire,and

[0045]FIG. 10B is a plan view thereof;

[0046]FIG. 11A is a side view showing the step after an upper conductivemember has been formed, and

[0047]FIG. 11B is a plan view thereof;

[0048]FIG. 12 is a schematic view showing the state where the lowerconductive member has been peeled off;

[0049]FIG. 13 is a characteristic view showing an experimental result ina mode for carrying out the invention; and

[0050]FIG. 14 is a characteristic view showing a wire-pull-strength.

PREFERRED EMBODIMENTS OF THE INVENTION

[0051] Referring to the drawings, an explanation will be given of modesfor carrying the invention. In the following description, in order toavoid overlapped explanation, like reference numerals refer to likeportions.

[0052] [First Embodiment]

[0053]FIG. 1 is a perspective view of a manner of connecting a wiringmember such as a lead frame 2 to a semiconductor chip through aconductive wire 12. The semiconductor chip 4 is mounted on the leadframe 2. The lead frame 2 is arranged on a stage 6 of a bonding device1. A wire spool 14 for the bonding device 1 houses a bonding wire usedfor bonding in a wound state. The bonding wire 16, when it is pulled outfrom the wire spool 14, is guided onto the stage 6 via a clamper 18 anda capillary 20. In this case, in the clamper 18, the bonding wire 16passes between a pair of holding plates 18 a and 18 b. In the capillary20, the bonding wire 16 further passes from the one end to the other endof a through-hole 20 a. At a cut end portion of the bonding wire 16, aball 16 a is formed in such a manner that the cut end is heated andmolten using a discharge conductive member 22. The stage is movable inboth X and Y directions in FIG. 1 in a state where the lead frame 2 andthe semiconductor chip 4 are placed. On the other hand, the capillary 20is movable in a Z direction.

[0054] The lead frame 2 includes a plurality of inner leads 2 a, 2 b andan island 2 c. The semiconductor chip 4 is connected to the island 2 cof the lead frame 2 by silver paste. On the main surface 4 a of thesemiconductor chip 4, a semiconductor device (not shown) and bondingpads 4 b and 4 c are formed. On the inner leads 2 a and 2 b, lowerconductive member 8 and 9 are formed, respectively.

[0055] In the case of a Si-family semiconductor device, the conductivemember pads 4 b, 4 c on the semiconductor chip are made of aluminum oraluminum alloy. In the case of a III-V group semiconductor device, theconductive member pads 4 b, 4 c are made of Au or Au alloy. The bondingwire 16 is a gold wire having a diameter of about 30 μm.

[0056] As seen from FIG. 1, the conductive member pad 4 b and inner lead2 a are connected to each other by means of a bonding wire. A conductivewire 12 is composed of a ball conductive member 12 a connected to theconductive member pad 4 b, a connecting end 12 b connected to the lowerconductive member 8 on the lead frame and a connecting wire 12 c whichconnects the ball conductive member 12 a and the connecting end 12 b. Anupper conductive member 10 is provided on the connecting end 12 b. InFIG. 1, an conductive member pad 4 c is to be connected to an inner lead2 b.

[0057] [Second Embodiment]

[0058] Referring to FIGS. 2A-4B, an explanation will be given of aseries of steps of connecting a lead frame 2 to a semiconductor chip 4mounted thereon.

[0059] First, lower conductive members 8, 9 are formed of inner leads 2a, 2 b. Although the lower conductive members 8, 9 can be formed ofbumps such as a gold bump, copper bump and a solder bump, they arepreferably formed in a convex shape which can be formed by melting thebonding wire 16 by discharge so as to be re-crystallized. In this way,the conductive member of a more soft material than the original wirematerial can be obtained. Since the lower conductive members 8,9 areformed by melting the wire having the diameter of about 30 μm to formthe ball and bump, the diameter of the lower conductive members 8, 9becomes several tens μm. The case where the wire is molten to form thelower conductive members 8, 9 will be explained below.

[0060] By moving the stage 6 and capillary 20, the convex-shaped ballconductive member (FIG. 1) formed at the tip of the bonding wire 16 isfixed to the inner lead 2 a. In this case, the crimping technique suchas thermal crimping and ultrasonic thermal crimping is used. First, thebonding wire 16 held by the holding members 18 a, 18 b is cut at theedge of the through-hole 20 a of the capillary 20. Thus, the lowerconductive members 8, 9 are formed on the inner leads 2 a, 2 b. FIGS. 2Aand 2B show the state after the above step has been completed. FIG. 2Ais a side view and FIG. 2B is an top view.

[0061] Thereafter, the lead frame 2 and the semiconductor chip 4 will beconnected to each other by the bonding wire 16. First, the cut end ofthe bonding wire 16 held by the capillary (20 in FIG. 1) is molten bydischarge to form a ball-shaped conductive member. The stage 6 is movedso that the ball-shaped conductive member is located on the bonding pad4 b of the semiconductor chip 4. Using the above crimping technique, theball-shaped conductive member is crimped on the bonding pad 4 b. Afterthe crimping, the bonding wire 16 is moved without being cut while it iscontinuously unreeled so that the bonding tool 20 is located on thelower conductive member 8 formed on the inner lead 2 a. After thebonding wire 16 has been bonded to the lower conductive member 8, it iscut. Likewise, the bonding pad 4 c is electrically connected to thelower conductive member 9. Thus, the bonding pads 4 b, 4 c of thesemiconductor chip 4 are connected to the inner leads 2 a, 2 b,respectively. The conductive wire 12 contains a ball conductive member12 a on the pad 4 b, a connecting end 12 b and a conductive wire 12 cconnecting them to each other. The conductive wire 13 contains a ballconductive member 13 a on the pad 4 c, a connecting end 13 b and aconductive wire 13 c connecting them to each other. FIGS. 3A and 3B showthe lead frame 2 and semiconductor chip 4 after the above step has beenexecuted. FIG. 3A is a side view and FIG. 3B is a top view.

[0062] Next, upper conductive members 10 and 11 are formed on the lowerconductive members 8 and 9. First, the cut end of the bonding wire 16held by the capillary 20 is molten by discharge to form a ball-shapedconductive member. The stage 6 is moved so that the ball-shapedconductive member is located on the lower conductive member 8 providedon the inner lead 2 a. Using the above crimping technique, theconnecting end 12 is crimped on the lower conductive member 8. After thecrimping, the bonding wire 16 is cut. Likewise, the upper conductivemember 11 is provided on the lower conductive member 9. Thus, the upperconductive members 10 and 11 are formed. The connecting end 12 b of theconductive wire 12 is sandwiched by the lower conductive member 8 andupper conductive member 9. The connecting end 13 b of the conductivewire 13 is sandwiched by the lower conductive member 8 and upperconductive member 9 from its both sides. FIGS. 4A and 4B show the leadframe 2 and semiconductor chip 4 after the above step has been executed.

[0063]FIGS. 5A and 5B are enlarged views showing the manner of bondingthe conductive wire 12 to the lower conductive member 8.

[0064]FIG. 5A shows the manner of fixing the conductive wire 12 to thelower conductive member 8. For example, the lower conductive member 8has a diameter of about 100 μm for the wire having a diameter of 30 μm.At the time of fixing, weight is applied from above in bonding.Therefore, the edge of the capillary 20 will be brought into contactwith the side of the conductive wire 12. Accordingly, the conductivewire 12 has a neck portion 12 d.

[0065] As seen from FIG. 5B, the connecting end 12 b of the conductivewire 12 is sandwiched between the upper conductive member 10 and thelower conductive member 8. Since the upper conductive member 10 isformed to cover the neck portion 12 d of the conductive wire 12 (theportion of the conductive wire 12 with which the edge of the capillary20 is in contact) from above, the strength of the neck portion 12 d iscompensated for. In the embodiments described above, all of the lowerconductive member 8, conductive wire 12 and upper conductive member 10are made of the same kind of materials. The bonding strength among thesethree members is greater than that among different kinds of materials.

[0066] The connecting end 12 b of the conductive wire 12 is sandwichedby the upper conductive member 10 and lower conductive member 8 from itsboth sides. For this reason, the total bonding area of the conductivewire 12 is increased as compared with the case of provision of only thelower conductive member 8, thereby increasing the bonding strength.

[0067] In fixing, since the lower conductive member 8 is deformed, thedeformation of the conductive wire 12 itself can be suppressed. As aresult, reduction of the sectional area in the neck portion 12 d of theconductive wire 12 can be suppressed. This effect is particularlyremarkable when the bonding wire 16 is recrystallized. The upperconductive member 10 is also formed by recrystallization of the bondingwire 16. Therefore, it is deformed in its bonding with the lowerconductive member. Namely, its shape can be easily changed in accordancewith the shape of the neck portion 12 d so that the neck portion 12 dcan be protected.

[0068] [Third Embodiment]

[0069] Now referring to FIGS. 6A-8A, an explanation will be given ofanother embodiment in which the wiring member is another semiconductorchip.

[0070] FIGS. 6A-8B correspond to FIGS. 2A-4B, respectively. As seen fromFIGS. 6A and 6B, another semiconductor chip 24 is mounted on an island 2d. On the main surface 24 a of another semiconductor chip 24, bondingpads 24 b and 24 c are formed. On these bonding pads 24 b and 24 c, thelower conductive member 8 and 9 are formed, respectively. Therefore, theexplanation of FIGS. 2A-4B can be applied to this mode except that thelower conductive members 8 and 9 are formed on the bonding pads 24 b and24 c, not but on the inner leads 2 a and 2 c.

[0071] This mode can also provide the same operation and effect as thatwhen the present invention is applied to the wiring member of a leadframe 2. In addition, if this connecting structure is provided, it ispossible to realize the wire connection between chips by using thebonding pads having substantially same size.

[0072] [Fourth Embodiment]

[0073] Now referring to FIGS. 9A-11B, still another mode will beexplained.

[0074] First, lower conductive members 8 a, 9 a are formed on innerleads 2 a, 2 b. The lower conductive members 8 a, 9 a are formed in aconvex shape formed by melting the boding sire 16 by discharge so as tobe re-crystallized as similar to the second embodiment.

[0075] By moving the stage 6, the ball conductive member (see, FIG. 1)formed at the tip of the bonding wire 16 is fixed to the inner lead 2 a.In this case, the crimping technique such as thermal crimping andultrasonic thermal crimping is used. After the crimping, the stage 6 ismoved to the positions different from the lower conductive members 8 a,9 a and the bonding wire 16 is fixed to the inner leads 2 a and 2 b.This fixing can be carried out without forming the ball, but may becarried out by forming the ball. After fixing, the bonding wire 16 heldby the holding members 18 a, 18 b is cut by the capillary 20. Each ofthe conductive wires thus formed is composed of a lower conductivemember 8 a, 9 a, conductive portion 8 c, 9 c and a wire portionconnecting them. The connecting portion 8 c, 9 c and the wire portion 8b, 9 b are extended from the lower conductive member 8 a, 9 a. Thispermits the tension applied to the bonding portion to be dispersed.FIGS. 9A and 9B show the state after the above step has been completed.FIG. 9A is a side view and FIG. 9B is an top view.

[0076] Thereafter, the lead frame 2 and the semiconductor chip 4 will beconnected to each other by the bonding wire 16. First, the cut end ofthe bonding wire 16 is molten by discharge to form a ball-shapedconductive member. The stage 6 is moved so that the ball-shapedconductive member is located on the bonding pad 4 b of the semiconductorchip 4. Using the above the crimping technique, the ball-shapedconductive member is crimped on the bonding pad 4 b. After the crimping,the bonding wire 16 is moved without being cut while it is continuouslyunreeled so that the capillary 20 is located on the lower conductivemember 8 formed on the inner lead 2 a. After the bonding wire 16 hasbeen fixed to the lower conductive member 8, (the bonding wire 16 iscut. Likewise, the bonding pad 4 c is electrically connected to theinner lead 2 b by the above crimping technique. Thus, the bonding pads 4b, 4 c of the semiconductor chip 4 are connected to the inner leads 2 a,2 b, respectively. The conductive wire 12 contains a ball conductivemember 12 a on the pad 4 b, a connecting end 12 b on the lowerconductive member 8 a and a conductive wire 12 c connecting them to eachother. The conductive wire 13 contains a ball conductive member 13 a onthe pad 4 c, a connecting end 13 b on the lower conductive member 9 aand a conductive wire 13 c connecting them to each other. FIGS. 10A and10B show the lead frame 2 and semiconductor chip 4 after the above stephas been executed. FIG. 10A is a side view and FIG. 10B is a top view.

[0077] Next, upper conductive members 10 a and 11 a is formed on thelower conductive members 8 and 9. First, the cut end of the bonding wire16 is molten by discharge to form a ball-shaped conductive member. Thestage 6 is moved so that the ball-shaped conductive member is located onthe connecting end 2 b of the conductive wire 12. Using the abovecrimping technique, the connecting end 12 b is crimped on the lowerconductive member 8 a. After the crimping, the bonding wire 16 is fixedto the inner lead 2 a at a different position from the lower conductivemembers 8 a. The bonding can be carried out by the same technique as thecrimping. Likewise, the upper conductive member 11 a is formed on theconducting end 13 b of the conductive wire 13 and bonded to the innerlead 2 b at the position 11 c different from the lower conductive member9 a. Thus, the one connecting member contains the upper conductivemember 10 a, connecting portion 10 c and wire portion 10 b connectingthem, whereas the other connecting member contains the upper conductivemember 11 a, connecting portion 11 c and wire portion 11 b connectingthem. The connecting end 12 b of the conductive wire 12 is sandwiched bythe lower conductive member 8 a and upper conductive member 10 a fromits both sides. The connecting end 13 b of the conductive wire 13 issandwiched by the lower conductive member 9 a and upper conductivemember 11 a. FIGS. 11A and 11B show the lead frame 2 and semiconductorchip 4 after the above step has been executed. FIG. 11A is a side viewand FIG. 11B is a top view.

[0078] This embodiment can also provide the same operation and effect asthe second embodiment. Namely, on the lower conductive member 8 a, 9 aand connecting end 12 b, 13 b, the upper conductive member 10 a, 11 amade of the same material as that of these members is provided. Thefixing area of the connecting ends 12 b, 13 b of the conductive wireswith the upper and lower conductive members is increased. Further, theupper conductive members 10 a, 11 a is formed to cover the connectingend 12 b, 13 b of the conductive wire 12, 13. Therefore, the upperconductive members 10 a serves to protect the neck portion of theconductive wire 12, 13 from above. Such a structure can greatly improvethe breaking strength against the tension applied to the conductive wire12.

[0079] Further, in this embodiment, an anchor structure is provided inwhich the upper conductive member 10 a (11 a) and the connecting portion10 c (11 c) formed integrally with it and the corresponding lowerconductive member 8 a (9 a) and the connecting portion 8 c (9 c) formedintegrally with it are fixed to the inner lead 2 a (2 b) at a pluralityof positions. Such a structure permits the tension applied to theconductive wire 12, 13 to be dispersed at the plurality of fixingpoints. The anchor structure can be adopted in at least one of the lowerconductive member and upper conductive member.

[0080] If the separation as shown in FIG. 12, the anchor structureprevents the electrical connection and mechanical bonding from beinglost completely.

[0081] The method according to the invention can be applied to thesemiconductor chip 4, 24 having at least one of the a light receivingelement and a light emitting element, or any other active elements.

[0082] The semiconductor chip 4, 24 in which the electrical connectionto the conductive wire has been completed can be sealed together withthe lead frame 2 using mold resin. Further, the semiconductor chips 4and 24 are integrally or individually sealed by mold resin.

[0083] After the semiconductor chip 4, 24 is electrically connected tothe wiring member so that the neck portion 12 d is protected by theupper conductive member 10, it is sealed using the mold resin. For thisreason, when the stress is applied to the conductive wire 12 owing tothe expansion and shrinkage of the mold resin for sealing, theconductive wire 12 is difficult to break at the neck portion 12 d. Withrespect to the resin for sealing the light receiving and light emittingelements, the resin should be permeable to the light having a wavelengthin which these elements has sensitivity. Therefore, the stressrelaxation agent which relaxes the stress of the mold resin can not beadded to the resin. However, the semiconductor device according to theinvention can be effectively applied to such a case.

[0084]FIG. 13 shows the result of the breakage strength test executedfor the semiconductor device shown in FIGS. 4A and 4B according to themode for carrying out the invention. In FIG. 13, the abscissa indicatesthe breakage strength of the neck portion in gram (g), and the ordinateindicates its occurring frequency in a relative value. In FIG. 13, threeremarkable peaks A, B and C appear. Peak A is located at the position ofthe breakage strength of about 15 g which corresponds to the datarelative to the conventional structure in which both lower conductivemember and upper conductive member are not provided. Peak B is locatedat the position of the breakage strength of about 25g which correspondsto the structure in which the upper conductive member is not provided.Peak C is located at the position of the breakage strength of about 33gwhich corresponds to the structure according to the invention in whichboth lower and upper conductive members are provided. In the order ofthe peak A-peak C, the dispersion is decreased. Thus, it has beenverified that the structure corresponding to the peak C exhibits notonly a great strength but also stabilized characteristic.

[0085] It was verified from the experiment by the inventors that thethickness of the lower conductive member is preferably 10 μ or more inthe modes for carrying out the invention. FIG. 14 is a characteristicview with the thickness d of the lower conductive member in abscissa andthe wire-pull-strength indicative of a wire pulling strength inordinate. The thickness d of the lower conductive member denotes thevalue when it is connected to the conductive wire.

[0086] The present invention is clearly different from the technologydisclosed in JP-A-55-118643. In the technology disclosed in thisreference, ball bond and stitch bond are made on the Al surface using abonding wire. In such a structure, the bonding wire is once connected tothe ball bond formed on the Al surface and thereafter extended to thestitch bond. Therefore, the bonding wire has no connecting end. Noconductive member is formed on the ball band. Therefore, the electricconnecting area between the bonding wire and ball bond is small andbonding area is also small.

[0087] As described in detail referring to the drawings, the connectingportion of the conductive wire to be connected to the wiring member issandwiched between the upper and lower conductive members. Therefore,the neck portion of the conductive wire can be protected by the upperconductive member so that the neck portion can be reinforced. Inaddition, the total bonding area of the conductive wire is increased ascompared with the case of the provision of only the lower conductivemember, and hence the bonding strength is increased. Further, since thelower conductive member is formed on the lower side of the connectingportion of the conductive wire, the lower conductive member is deformed.Therefore, the deformation of the conductive wire itself is suppressed.Thus, reduction in the sectional area of the neck portion of theconductive wire can also be suppressed.

[0088] In the method of manufacturing a semiconductor device accordingto the invention, the lower conductive member is provided before theconductive wire is connected to the wiring member. Therefore, it canprovide a conductive portion capable of absorbing the stress applied inbonding at the portion to which the conductive wire is to be fixed.Therefore, the deformation of the conductive wire can be suppressed.Further, since the upper conductive member is provided on the lowerconductive member through the conductive wire after the conductive wirehas been connected to the lower conductive member, the neck portion ofthe conductive wire formed when the conductive wire is connected to thelower conductive member can be protected by the upper conductive member.

[0089] Thus, in accordance with the invention, a semiconductor devicecapable of reducing breakage of a bonding wire and a method ofmanufacturing it can be provided.

What is claimed is:
 1. A semiconductor device comprising: a lowerconductive member formed on a wiring member to be electrically connectedto a semiconductor chip; a conductive wire having the one endelectrically connected to said semiconductor chip and the other endelectrically connected to said lower conductive member; and a upperconductive member formed on said lower conductive member so as tosandwich the other end of said conductive wire.
 2. The semiconductordevice according to claim 1, wherein said wiring member is a lead frameon which said semiconductor chip is mounted.
 3. The semiconductor deviceaccording to claim 1, wherein said wiring member is anothersemiconductor chip different from said semiconductor chip.
 4. Thesemiconductor device according to claim 1, further comprising mold resinfor sealing said semiconductor chip and said wiring member; wherein saidsemiconductor chip includes at least one of a light emitting element anda light receiving element, and a wavelength of the light, which saidlight emitting element and said light receiving element has sensivity,is permeable to said mold resin.
 5. A semiconductor device comprising: afirst connecting member having a lower conductive member formed on awiring member to be electrically connected to a semiconductor chip and aconnecting portion connected to said wiring member at a differentposition from said lower conductive member; a upper conductive memberformed on said lower conductive member; and a conductive wire having theone end electrically connected to said semiconductor chip and the otherend sandwiched said lower and upper conductive members and electricallyconnected to said lower conductive member.
 6. The semiconductor deviceaccording to claim 5, wherein said wiring member is a lead frame onwhich said semiconductor chip is mounted.
 7. The semiconductor deviceaccording to claim 5, further comprising mold resin for sealing saidsemiconductor chip and said wiring member; wherein said semiconductorchip includes at least one of a light emitting element and a lightreceiving element, and a wavelength of the light, which said lightemitting element and said light receiving element has sensivity, ispermeable to said mold resin.
 8. A semiconductor device comprising: afirst connecting member having a lower conductive member formed on awiring member to be electrically connected to a semiconductor chip and aconnecting portion connected to the wiring member at a differentposition from said lower conductive member; a second connecting memberhaving an upper conductive member formed on said lower conductive memberand a connecting portion connected to said wiring member at a differentposition from said lower conductive member; and a conductive wire havingthe one end electrically connected to said semiconductor chip and theother end sandwiched between said lower conductive member and said upperconductive member and electrically connected to said lower conductivemember.
 9. The semiconductor device according to claim 8, wherein saidwiring member is a lead frame on which said semiconductor chip ismounted.
 10. The semiconductor device according to claim 8, furthercomprising mold resin for sealing said semiconductor chip and saidwiring member; wherein said semiconductor chip includes at least one ofa light emitting element and a light receiving element, and a wavelengthof the light, which said light emitting element and said light receivingelement has sensivity, is permeable to said mold resin.
 11. A method formanufacturing a semiconductor device in which a semiconductor chip and awiring member are electrically connected to each other, comprising: afirst step of forming a lower conductive member on said wiring member; asecond step of connecting the one end of a conductive wire to saidsemiconductor chip; a third step of connecting said conductive wire tosaid lower conductive member; and a fourth step of forming an upperconductive member on said lower conductive member through saidconductive wire.
 12. The method for manufacturing a semiconductor deviceaccording to claim 11, further comprising, after said fourth step, thestep of bonding a conductive portion extending from said upperconductive member to said wiring member at a different position fromsaid lower conductive member.
 13. The method for manufacturing asemiconductor device according to claim 11, further comprising, prior tosaid second step, the step of bonding a conductive portion extendingfrom said lower conductive member to said wiring member at a differentposition from said lower conductive member.
 14. The method formanufacturing a semiconductor device according to claim 11, furthercomprising, prior to said first step, a step of preparing thesemiconductor chip having one of a light receiving element and a lightemitting element and the wiring member; and a step of sealing saidwiring member and said semiconductor chip connected to said wiringmember through said conductive wire using mold resin; wherein the lightrelative to said light emitting element and said light receiving elementis permeable to the mold resin.